MAX11803 Maxim Integrated Products, MAX11803 Datasheet - Page 24

• Manufacturer Part Number: MAX11803
• Description: (MAX11800 - MAX11803) Ultra-Small Resistive Touch-Screen Controllers
• Manufacturer: Maxim Integrated Products

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Low-Power, Ultra-Small Resistive Touch-Screen
Controllers with I
To simplify measurement procedures, the MAX11800–
MAX11803 support three types of commands: panel
setup commands (PSU), panel measurement commands
(PMC), and combined measurement commands (CMC).
In direct conversion mode, the MAX11800–MAX11803
can use all three types of commands. Using individual
panel setup and measurement commands allow for a
high degree of customization based on decisions made
by the AP, while using combined commands signifi-
cantly simplifies the complete measurement process
and reduces communications between the AP and the
MAX11800–MAX11803.
In autonomous mode, the MAX11800–MAX11803 use
combined commands to control and automate all
aspects of panel setup, measurements, and timing. See
the Operating Mode Configuration Register (0x0B) sec-
tion for more details.
In direct conversion mode, the AP requests individual
panel setup and conversion operations or automated
Figure 8. State Machine Transitions (Direct Conversion Mode)
24
Panel Setup, Measurement, and Scan Commands
______________________________________________________________________________________
Direct Conversion Mode Operations
COMMAND
COMMAND
COMMAND
NO
NO
NO
SETUP
SETUP
SETUP
PANEL
PANEL
PANEL
X
Y
Z
INTERNAL TRANSITION
USER COMMAND
CONVERSION
AVERAGE
2
DETECT
X
C/SPI Interface
CONVERSION
CONTINUOUS
LAST
DONE AND
DETECT
TOUCH
ACQUIRE
combinations of measurements (X and Y, X and Y and
Z1, or X and Y and Z1 and Z2 combined). Unlike
autonomous conversion modes, the AP maintains control
over the initiation of panel setup, measurements events,
and the sampling frequency. Figure 8 shows the state
machine transitions for direct conversion mode.
The MAX11800–MAX11803 support two direct conver-
sion interrupt modes. The two direct conversion modes
are the continuous interrupt mode (CINT) and the edge
interrupt mode (EINT).
In continuous interrupt mode, the panel returns to TDM
and idle. The current status of the panel is then sent
through TIRQ. The continuous interrupt mode is the
least efficient mode in current consumption for long
duration of touches. The power consumption is approxi-
mated by P
tion levels observed when the panel is not touched is
limited by the junction leakage currents of the
MAX11800–MAX11803.
Y
ACQUIRE
TOUCH-
DETECT
PULLUP
Z1
FINE
TOUCH
ACQUIRE
TIME IS UP
Z2
CONVERSION
AVERAGE
= V
DD
TIME IS UP
2
Continuous Interrupt Mode
ACQUIRE
/R
AUX
PU
. The power consump-
CONVERSION
CONTINUOUS
LAST
DONE AND
Interrupt Modes
TOUCH-
PULLUP
DETECT
FINE